1. Field of the Invention
The present invention relates to an earphone microphone and particularly to an earphone microphone including a speaker and a microphone.
2. Description of Related Art
Conventionally, there is known an earphone microphone including a speaker and a microphone. A user who puts on the earphone microphone can transmit his or her voice input to the microphone while hearing sound such as speaking voice output from the speaker. Therefore, the earphone microphone is used for handsfree communication with a cellular phone or the like.
In general, a canal type of the earphone microphone such as described in JP-A-2007-201887 is often used. When a user puts on a canal type earphone microphone placed in an ear, the external acoustic meatus of the user is sealed by a main body of the earphone microphone. Therefore, the microphone, which is in the closed space including the user's auditory meatus and an inner space of a main body case of the earphone microphone, picks up little external noise. Therefore, noise is hardly mixed into the voice input to the microphone for transmitting the user's voice.
However, in the canal type earphone microphone as described in JP-A-2007-201887, because the microphone picks up sound in the sealed acoustic space, the transmitted voice is apt to have a muffled feeling compared with the real voice. In particular, there is a problem that a high frequency voice is apt to be muffled so that voice deteriorated from the real voice is transmitted. On the other hand, if the earphone microphone is an inner ear type, the voice sound picked up by microphone is hardly with muffled feeling. However, because the user's external acoustic meatus is not sealed by the inner ear type earphone microphone, the microphone easily picks up external noise. Further, low frequency vice output from the speaker becomes hardly heard. Therefore, sound quality is deteriorated.